Molecular analysis of two ScrR repressors and of a ScrR–FruR hybrid repressor for sucrose and D‐fructose specific regulons from enteric bacteria

Jahreis, Knut; Jw, Lengeler

doi:10.1111/j.1365-2958.1993.tb01681.x

Cited by 36 publications

(35 citation statements)

References 57 publications

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“…Hydrolysis of sucrose 6-phosphate by S6PH yields G6P and fructose, and for K. pneumoniae, fructose is believed to be the inducer of the scr operon (Jahreis & Lengeler, 1993). Hydrolysis of the phosphorylated isomers by AglB of K. pneumoniae also yields G6P and fructose, and formation of the latter ketohexose is consistent with the high levels of S6PH and FK present in cells grown on the isomers (Table 2).…”

Section: Discussionsupporting

confidence: 54%

Metabolism of sucrose and its five isomers by Fusobacterium mortiferum

et al. 2002

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Fusobacterium mortiferum utilizes sucrose [glucose-fructose in α(1 2) linkage] and its five isomeric α-D-glucosyl-D-fructoses as energy sources for growth.Sucrose-grown cells are induced for both sucrose-6-phosphate hydrolase (S6PH) and fructokinase (FK), but the two enzymes are not expressed above constitutive levels during growth on the isomeric compounds. Extracts of cells grown previously on the sucrose isomers trehalulose α(1 1), turanose α(1 3), maltulose α(1 4), leucrose α(1 5) and palatinose α(1 6) contained high levels of an NAD M plus metal-dependent phospho-α-glucosidase (MalH). The latter enzyme was not induced during growth on sucrose. MalH catalysed the hydrolysis of the 6'-phosphorylated derivatives of the five isomers to yield glucose 6-phosphate and fructose, but sucrose 6-phosphate itself was not a substrate. Unexpectedly, MalH hydrolysed both α-and β-linked stereomers of the chromogenic analogue p-nitrophenyl glucoside 6-phosphate. The gene malH is adjacent to malB and malR, which encode an EII(CB) component of the phosphoenolpyruvate-dependent sugar :phosphotransferase system and a putative regulatory protein, respectively. The authors suggest that for F. mortiferum, the products of malB and malH catalyse the phosphorylative translocation and intracellular hydrolysis of the five isomers of sucrose and of related α-linked glucosides. Genes homologous to malB and malH are present in both Klebsiella pneumoniae and the enterohaemorrhagic strain Escherichia coli O157 :H7. Both these organisms grew well on sucrose, but only K. pneumoniae exhibited growth on the isomeric compounds.

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Section: Discussionsupporting

confidence: 54%

Metabolism of sucrose and its five isomers by Fusobacterium mortiferum

et al. 2002

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“…The genes mediating sucrose uptake and hydrolysis are usually clustered on the chromosome and form operons or regulons (2,4,7,8,13,21,31,35,37) (GenBank accession number L32093). Regulation of the sucrose utilization system is best studied in Bacillus subtilis, in which positive control involves a transcriptional antitermination mechanism (1,11,22).…”

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confidence: 99%

“…Regulation of the sucrose utilization system is best studied in Bacillus subtilis, in which positive control involves a transcriptional antitermination mechanism (1,11,22). In a number of gram-negative bacteria, repressor proteins of the GalR-LacI family negatively control the expression of the sucrose genes (3,4,8,21). Since several gram-positive bacteria carry homologous putative regulatory genes close to the sucrose gene clusters (31) (GenBank accession numbers L32093 and M36849), they may employ a similar negative regulation mechanism.…”

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Transcriptional regulation of the sucrase gene of Staphylococcus xylosus by the repressor ScrR

Gering

Brückner

1996

J Bacteriol

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In Staphylococcus xylosus, scrB is one of two genes necessary for sucrose utilization. It encodes a sucrase that hydrolyzes intracellular sucrose-6-phosphate generated by the uptake of sucrose via the sucrose-specific enzyme II of the phosphotransferase system, the gene product of scrA. ScrB sucrase activity is inducible by the presence of sucrose in the culture medium. Primer extension experiments demonstrated that the observed regulation is achieved at the level of scrB transcription initiation. The protein mediating sucrose-specific regulation of scrB was found to be encoded

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“…Gel mobility shift assays with the 300-bp DNA fragment preceding scrY and the repressor showed that ScrR binds to this region and that fructose and not sucrose is the molecular inducer of scrYAB transcription, as in pUR400 and K. pneumoniae. The scr repressors of pUR400 and K. pneumoniae interact with a helix-turn-helix with the operator palindrome TAAACC/GGTTTA preceding scrY and scrK and bind to fructose or fructose 1-phosphate but not to sucrose (34). A part of this sequence (AACC/GGTT) was found in front of scrY and is possibly the operator in the scr regulon of E. amylovora.…”

Section: Discussionmentioning

confidence: 99%

“…The scr regulons of K. pneumoniae and pUR400 consist of four structural genes: scrK codes for an ATP-dependent fructokinase (5), scrY codes for a sucrose-specific porin of the outer membrane (30), scrA codes for enzyme II scr of the PTS, and scrB codes for an intracellular ␤-D-fructofuranoside fructohydrolase (EC 3.2.1.26), which cleaves sucrose 6-phosphate into ␤-D-fructose and ␣-D-glucose 6-phosphate (51). The regulon is controlled by the negative regulator ScrR (34) and is induced in medium containing sucrose, fructose, or raffinose (45,46).…”

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Molecular Analysis of Sucrose Metabolism of Erwinia amylovora and Influence on Bacterial Virulence

Bogs

Geider

2000

J Bacteriol

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Sucrose is an important storage and transport sugar of plants and an energy source for many phytopathogenic bacteria. To analyze regulation and biochemistry of sucrose metabolism of the fire blight pathogen Erwinia amylovora, a chromosomal fragment which enabled Escherichia coli to utilize sucrose as sole carbon source was cloned. By transposon mutagenesis, the scr regulon of E. amylovora was tagged, and its nucleotide sequence was determined. Five open reading frames, with the genes scrK, scrY, scrA, scrB, and scrR, had high homology to genes of the scr regulons from Klebsiella pneumoniae and plasmid pUR400. scrB and scrR of E. amylovora were fused to a histidine tag and to the maltose-binding protein (MalE) of E. coli, respectively. ScrB (53 kDa) catalyzed the hydrolysis of sucrose with a K m of 125 mM. Binding of a MalE-ScrR fusion protein to an scrYAB promoter fragment was shown by gel mobility shifts. This complex dissociated in the presence of fructose but not after addition of sucrose. Expression of the scr regulon was studied with an scrYAB promotergreen fluorescent protein gene fusion and measured by flow cytometry and spectrofluorometry. The operon was affected by catabolite repression and induced by sucrose or fructose. The level of gene induction correlated to the sucrose concentration in plant tissue, as shown by flow cytometry. Sucrose mutants created by site-directed mutagenesis did not produce significant fire blight symptoms on apple seedlings, indicating the importance of sucrose metabolism for colonization of host plants by E. amylovora.The gram-negative bacterium Erwinia amylovora causes fire blight of apple, pear, and other rosaceous plants. Pathogenecity depends on the ability to produce the exopolysaccharide amylovoran (10, 13), to elicit a hypersensitive response on non-host plants (6,8), and to metabolize sorbitol of the host plants (1). Rosaceous plants contain sorbitol and sucrose as storage and transport carbohydrates. The distribution of these carbohydrates is dependent on environmental conditions, species, and plant tissue (28, 52). The highest concentration of sucrose was found in the nectaries of host plants (14), which are assumed to be the main entry site for the pathogen when the pathogen is distributed by insects.Sucrose is utilized by some but not all bacteria extracellularily or intracellularily. E. amylovora can metabolize sucrose via the secreted levansucrase, which polymerizes the homopolysaccharide levan and releases glucose from sucrose (27,29), but also by uptake and intracellular metabolism.The sucrose-utilizing system of enteric bacteria has been studied in Klebsiella pneumoniae and in some isolates of Escherichia coli and Salmonella spp. (45, 49). In E. coli and Salmonella spp., the conjugative plasmid pUR400 confers the ability to utilize sucrose (54), whereas the scr regulon of K. pneumoniae is located on the chromosome (42, 49). In these bacteria, the uptake of sucrose is mediated via the phosphoenolpyruvate-dependent carbohydrate:phosphotransferase system (PTS),...

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Molecular analysis of two ScrR repressors and of a ScrR–FruR hybrid repressor for sucrose and D‐fructose specific regulons from enteric bacteria

Cited by 36 publications

References 57 publications

Metabolism of sucrose and its five isomers by Fusobacterium mortiferum

Metabolism of sucrose and its five isomers by Fusobacterium mortiferum

Transcriptional regulation of the sucrase gene of Staphylococcus xylosus by the repressor ScrR

Molecular Analysis of Sucrose Metabolism of Erwinia amylovora and Influence on Bacterial Virulence

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